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Sediment in a hot water heater.

Recently there has been posts about draining hot water heaters and the pros as well as the cons in doing this. Typical maintenance on a hot water heater is to flush the bottom drain at least once a year. In some towns where they flush their fire hydrants to keep the pipes clear it is suggested to follow their lead a few days after as any sediment that is disturbed ends up on the bottom of your heater.
What happens then is water displacement. The sandy partials that collect on the bottom of the tank displaces the water ever so slightly. This results in hot spots on the bottom of the tank. When this occurs the flames overheat the tank and begin to break down the steel. After many years this breakdown ends up becoming a tiny hole that is filled with this debris, oftentimes preventing the leak.
However if you decide to drain your heater after many years of not doing it, or all of a sudden you start using the heater more then normal, this sediment that has been plugging that tiny hole is flushed out, often resulting in a leak in a few days after.
So the moral is to flush yearly, but if you have not done so for many years to not touch it or you will end up with a leak.
After draining you may find that the flush hose bib valve at the bottom will not turn off. This is because of some sediment that has blocked the valve and prevented it from turning off. If that happens a hose bib cap can be purchased at the local hardware store for about $1.50 put that on and your good to go. The photo is the inside of such a valve on a hot water heater that was 6 years old and had never been flushed. We tried to empty this tank to replace with a new high efficiency tankless, next photo but the hole was so small it only trickled out. The new heater will produce enough hot water for two showers, one laundry and one dishwasher to run all at the same time.

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  • Jamala W
    Jamala W Whitmire, SC
    on Mar 20, 2013

    thanks for the info

  • Leslie D
    Leslie D Las Vegas, NV
    on Mar 20, 2013

    Great info. We're in Las Vegas, with extremely hard water and our gas water heater is about 20 years old and has made loud bubbling sounds after using hot water (although it functions perfectly) ever since we moved in (6 years ago). We're thinking of replacing the sacrificial anode rod, but doubt that it has ever been changed before and are afraid of just stirring up sediment or even having the rod break off inside if it's severely corroded. It has a 6-year tank warranty, so I'm assuming there's only one rod and probably not much of it left by now. Your thoughts on whether it would be beneficial to even bother changing the rod, or is it just time to replace it?

  • You have got all the use out of the hot water heater your going to get. The Sacrificial anode rod at this point in time would not be worth the effort. While it does save corrosion on the inside of the heater it does nothing to the efficiency of its operation and the hot water heaters made to day are way more efficient then those that long ago. The bubbling sound is air. This is caused by the build up of minerals on the inside of the heater. An example of this is to take a pot of water put it on the stove and boil water. By magic air is released from very tiny dots on the bottom of the pan. If you were to place a few stones on the bottom of the pot, to create the build up of what is in the bottom of the heater, you will see even more bubbles come from those areas. This noise is a sign that your nearing the end and should be replacing the unit sooner rather then later. On the anode rod, it should not break off as it does not build up with debris it is eaten so the only thing left would be a thin metal rod where once the rest of the rod once existed. It is just about impossible to remove these anyway. Lastly on warranties of hot water heaters. They are all pretty much the same on the inside from each manufacture. The primary difference is the size of the anode rod. The larger the rod is the longer the warranty would be. Also getting these rods can prove difficult in many areas of the country. As almost no one removes them and replaces them. A hot water heater is like that Uncle no one wants to see. Once it is in place it gets forgot until someone gets a cold shower.

  • HomeSpot HQ
    HomeSpot HQ Durham, NC
    on Mar 20, 2013

    One trick that I like is dumping a citric-acid-based cleaning product into the tank late at night (when nobody is using the water) and flushing it the next morning. For areas with hard water a "sludge" sometimes builds up at the bottom of the tank and the acid loosens it up.

  • Leslie D
    Leslie D Las Vegas, NV
    on Mar 20, 2013

    Thanks, Woodbridge. We assumed it was just time to replace it, and since our local Habitat for Humanity Restore currently has several brand new Rheem 40 gal gas water heaters for $200 each, I think we'll just do it. I would hate to have my garage flood with all the building materials we have collected stored in there.

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